The mind's geography is based on open-pit mines.  I think it works well as a representation of a person's memory-space on account of it being artificial terrain, yet still somewhat resembling a natural occurrence. Which is also the reason behind the basalt forms but the other way around. Also the player is literally digging around for memories.

I am placing each memory scene on a circle, going clockwise.  Their elevation corresponds to a basic narrative arc.

I tried forming the walls of the mine with the basalt columns but it took a heavy toll on the performance and it was not easy on the eyes either. So I used them to mark the edges of the map and distort the scale of things.